Liquid level gauge



May j13, 1952 l E. c. HAArvEDT LIQUID LEVEL GAUGE Filed oct. 9, 1948 INVENToR EF1/ /Yaazuedi BM ATTORNEYS Patented May 13, 1952 UNITED STATES PATENT oFF-rca ErvinA Ci Hifatucdt,y Brooklyn, N., Y., assignorto; Visnaageilnc,acornorativnofflew York;

nnlvniohctvbef 9, 1948i, Serial; N.. 53,615.

61 claims-i (01. '13e-293i Thief invention relatesl to a liquid gaugeA ormea'sur-ing instrument, more particularly of the typatormeasurel the level `of liquidi in a closed oontainerior tank and2 to an! ii-lstallaticn in which said instrument is i incorporated asa-y fixture;

Where-.gauges are used-l onliquid tanks thatv hauemechanieal: movingg parts, -oats cables and dials, the; movi-ngparts may. becomel deranged,

especiallyl when used on a moving! vehicle such-- asi-a railroad tank' cany air-plane, oil tanker crthe.

Where sigh-t gauges-Which includeshollow-glassl tubes and fittings which are connected to the exterior off-the tanklarel used to indicate. the liquid level, the: tubes andthe ttings' may-readily clog anda iin addition-varying pressure would affect-the accuracy of. the indication inthe tube.

Inbotnof these'ty-pesof-installations, constant maintenance and repair would be -necessaryand atbest .the user couldf never be sure ofthe ao'- curacy- 'of the device.

Where` ai direct indicating type of measuring instrumentV is lused, suchasa calibrated stick,l if the latter is merelypushed: into the liquid and then removedlto-J see what portion `of the lengthr thereofA has;- become Wet,' itis extremelydifcult andzrawkward to` make` suchl readings, especially- Where 'a largetankis beingv measuredv and the stick islong;V Inaddition the readingis ver-yapt to be.l inaccurate. `for the liquid m'aysplash 'when thefmeasuring 'stick inserted therein- -t'o-"give too highfa.- reading.;

Where a` volatile liquidi' such as: gasoline/is-y measured` by the-aboveiprocedure, yeacli'tinieithetank is opened to admit of a measurement, the hazard? of sparking andexplosion isincurred, aside :from Waste due-Sto` eva-poration;

Where v such 4 measuringv stick' isfixed: in" theLA liquiditank; it is necessary to provide a Windowv ofA some sort through- .Whichl the calibrations on theimeasuringfstick maybe read andto illuminate such. calibrations, an electriculight rnustbeV provided; If thev light-'was inside thetank, it

, would haveto; be at the toplthereof; andlin the casefof large. tanks quitepowerful: in order to illuminate; the enti-re.lengthlof` the calibratedsticki nomatter what level the liquid should at'. tain. However; inv such Vcase .thelight wouldblind the observer and render it diicult if not impossi. ble for him'toread the calibrations. This is also true. if the lightfis positionedv outside the. tank and the` raysl therefrom are` directedl intok the.

tank-- Where the,- lisbtisfnside the tank, it would Sem-become obscur d1-by the; @Irvine-affine ,f

2 contents thereon, making it difllcult to read the calibrationslonthe measuringsticl. In addition, Withthe'use of alight-inside the tankg iff`- itshould break in--a tank-of-volatile or inflammable liquid,`

the live electr-ic- Wires would probably cause nreI andi explosion with resultant'danger to the user and! destruction of-the` vehicla'shlpor apparatus'.

It -isaccordingly-amongethe obj eotfof' the invention to provide a' niieasli-ringdevice that is lightA inL Weight, th-atis devoid of mechanical moving parts, floats, cables or dials that may sti-ck or become out-of order, that is devoid/ofpipes, tubesfor tting-st-hat'may-beoome clogged, and the acouracy-'oflwhichis notaffected by varying pressures, that may readily be installed' in a liquid tank Withbut a minimum of expenseand that once installed-mayreadily be read Without opening the tan-k; that Arnayreadily-- be removed' forA cleaning-and-rnaintenaricei that' does. not requi-re electriclights orother illuminating means to be installedinthetank,y yetthat clearly and accurately indicates the level of the liquid therein.

According tothe invention, a,-calibrated*rod,

stick onbarwhich--functions as a light-'conduit is inserted into the tank, the liquif'- levelf of: which is to beV measured; Withthe fupper-` end of therod protrudingfrom the-surface oi-V the tank, A window isprovided. n-thesurfaCe of thetank toY afforda ela-r-'vieW-'of-th'e length ofu therod and allso'urce off-lig-h-tisv applied to the protr'iidingV end of# the rod"- to illuminate the length tnereof Preferably. the-redis: delight-"conductingmaterial andthe length, thereof-Within theliquid Figj- 1e isfa fragmentaryperspective View of a' liquidi tank-With -parts'- broken away to snow-I the] gauge installation;

Fig." 24 is, a: fragmentary longitudinal' cross-'- sectional view von. a larger 'scala` taken: along'- line E igi B :is a fragmentary perspective-view ofthe measuring-rod andf y Eia- 4 .ris a, fragmentarycr0sS--- sectional new Y 3 with parts broken away of another embodiment of the device.

Referring now to the drawings, the device comprises a rod or stick I|, preferably rectangular in cross section, though it may be round, oval, triangular or other suitable cross-section, of a light transmitting material such as Lucite or similar plastic, the inherent characteristics of which are such as to permit light to pass longitudinally through the length thereof, but to preclude lateral escape of the light so long as the outer surfaces of the rod are highly polished. The rod II is therefore preferably polished on its rear face and two side faces as at |2 and -has a roughened front face |3 on which the calibrations I4 are formed, and has desirably, though not necessarily, a roughened surface I at the upper end thereof against which light may be directed.

As shown'in Fig. 3, the calibrations are preferably engraved in the face I3 and painted with an opaque material to form a dark outline on the face I2. However, the calibrations could be painted directly on the roughened face I3 or all four faces of the rod could be highly polished and only the calibrations roughened to enable the light to pass laterally therethrough to illuminate the same and enable them to be clearly visible or the calibrations could be formed by drilling a plurality of holes into the rod to define the outline of such calibrations.

Rod |I is positioned with the upper portion I9 thereof passing through an opening 2| in the top of the tank I8 and with the length of the rod extending downwardly into said tank, as shown in Fig. l. In order rigidly yet removably to support rod |I, a hub 22 is provided, aflixed as by welding to the upper surface of the tank encompassing opening 2| therein. Hub 22 has an opening 23 therein larger in size than said rod and also larger than opening 2| in the container.

Positioned in the opening in hub 22 and seated on the rim 24 about opening 2| in the tank I8 is a gasket 25, preferably of rubber, having an opening 25 therethrough and provided with a rim 21 on the face thereof, preferably integral therewith, rim 21 forming a shoulder 28. Desirably rim 21 defines a substantially rectangular cup to receive a correspondingly shaped collar 29 which may also be of plastic rigidly connected to rod I I,as shown at an angle of approximately 45 degrees thereto. A second gasket 3| is also provided, preferably of rubber, having an opening 32 therethrough and provided with a rim 33 on the face thereof, preferably integral therewith, vrim 33 forming a shoulder 34. Desirably rim 33, like rim 21, also forms a substantially rectangular cup and rims 21 and 33 are of such size that when the upper portion I9 of rod II is passed through opening 32 in gasket 3|, the faces of rims 21 and 33 will abut, the cups defining a rectangular cavity in which collar 29 may be positioned.

As shown in Fig. 2, the side wall 35 of gasket 3| is beveled and coacts with the correspondingly beveled portion 3B of the wall of opening 23 in hub 22 to form a seal. In order to clamp gaskets 25 and 3| together securely to hold the collar 29 therebetween, and to form a liquid and gas tight seal about opening 2| in the tank, a lock ring 31 is provided having an opening 38 therein through which portion I9 of rod I| extends. Ring 31 is seated on the upper surface 39 of hub 22 and secured thereto by screws 4I threaded into hub 22. As the upper surface of gasket 3| normally extends slightly above the surface 39 of hub 22 and as rim 21 and rim 33 is each slightly greater in thickness than one-half the thickness of collar 23, when screws 4| are tightened the rubber gaskets will be compressed, forming a seal at the abutting faces of the rims and at the beveled portion 35 of this gasket 3|.

In order to provide support for the length of the inclined rod I| in the tank I8, respectively Where the latter is of large size, a channel member 43 may be provided, on the face 44 of which rod I I rests, with the side walls 45 of the channel member straddling rod I The upper end of the channel member 43 desirably has a projecting finger 41 extending horizontally therefrom and affixed as by welding to the under face of the roof of the tank. To reinforce the channel member 43, a plurality of braces 41 are desirably provided, two being illustratively shown in Fig. 1, extending transversely across the tank and afxed to the side walls thereof as by welding. As is illustratively shown in Fig. 1,'the braces are positioned so as to support the channel bar at an angle of approximately 45 degrees.

Desirably a cover is provided forv the upper end of the rod to protect it against injury. The cover may comprise a cup 4B, the depending wall of which has an internally threaded rim 49 which coacts with a correspondingly threaded portion 5I on the periphery of hub 22.

In order to read the calibrated rod a window 52 is provided in the top of tank I8. The window is positioned over the inclined face I3 of rod Ii and desirably comprises a hub 53 having an opening 54 therein, said hub being aixed to the top of the tank as by welding and encompassing an opening 55 therein. A lens 56 is also provided having a rubber collar 51 around the periphery thereof, as shown in Fig. 2. The collar is of such diameter that it will snugly fit into the opening 54 and when seated on the rim 58 about opening 55 will extend slightly above the upper surface of hub 53. In order to retain the lens in place, a clamp ring 60 is provided which may be secured to the top of hub 53 by screws 6| threaded into said hub. When screws 6| are tightened, they will force ring 60 against collar 51 to compress the latter and make an air and liquid tight seal about opening 55. To protect lens 56, a cover cap 62 is preferably provided, the depending wall 53 of which is threaded at its rim 54 which coacts with a correspondingly threaded portion on the periph- I ery of hub 53.

To use the device after it yhas been installed as above described, to determine the level of the liquid in the tank, the attendant need merely unscrew covers 48 and 62 and apply a source of light to the roughened end I0 of rod while looking through the window 52. The light may be from a flashlight, an electric bulb or the like, or during the day, sunlight may be sufficient.

As the light passes through the rod |I, the roughened face' I3 thereof will intercept the rays of light and glow brightly and hence the opaque calibrations thereon will stand out and may readily be seen through the window. With the tank partially filled with liquid, the face I3 of the portion of rod I I below the level of the liquid will not appear to glow brightly when seen through the window, due to the fact that evenwith a transparent liquid such as water or alcohol, the light passing therethrough will be diifused. Hence a sharp line of demarcation will appear on the rod at the liquid level which may lreadily be read by the observer.

In Fig. 4 in which corresponding parts have the same reference numerals primed, an alternative construction for cover 48 is shown.

Cover 48 has an opening 54 therein which is aligned with the top I0 of rod ll. A threaded cap 65 is provided, having an opening 66 therein and affixed as by welding on cover 48 with openings 66 and, 64 aligned. A conventional ashlight 61, preferably tubular as shown, is threaded into cap 65 to be securely retained therein in upright position. To take a reading it is only necessary to move switch 68 of the flashlight which will thereupon cast rays of light on roughened surface I0 of rod Il. In either of the embodiments shown, when the tank is empty and it is desired to clean the rod, it is only necessary to remove the cover 48 on hub 22 and screws 4I The rod may vthereupon be withdrawn from the container carrying with it ring 31 and gasket 3| which are seated on gasket 25.

With the above construction, all readings may be made without opening the tank and hence there will be no danger of volatile fumes escaping which may readily catch on fire. The device may readily be installed in a tank without adding materially to the cost thereof, and as even the channel member 43 and supporting braces 41 may be dispensed with in small tanks for the stuing box and collar 29 will provide adequate support for the rod, even conventional tanks now on the market may be provided with the measuring device, for it is only necessary to make two openings in the wall thereof to provide for the window 52 and the stuing box.

Where the device is to be incorporated in very large tanks such as in those on oil tankers, as a large access port or manhole is available to provide entry into the tank for cleaning, it is readily a simple matter to install the channel member 43 and supporting braces 41.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope of the claims, it is intended that all matter contained in the above descripion or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. A liquid tank having an opening therein, a stuiiing box aixed to the outside of said tank about said opening, a measuring rod of light conducting material extending downwardly into said tank through said stuffing box and said opening and removably mounted therein, means in said stuffing box coacting with said rod securely to retain the latter in said tank, one end of said rod extending beyond said stuffing box and exposed on the outside of said tank, said exposed end having a roughened surface, whereby when rays of light are directed against said roughened surface they will pass through the length of said rod, said rod having calibrations along its length on the surface thereof and having roughened areas on said surface to intercept the rays of light passing therethrough to illuminate said calibrations to render them clearly readable, means in said tank to support said rod at an inclination with respect to the top thereof with said calibrations facing upwardly, and a window in the wall of said tank 6 positioned over said inclined rod, through which said calibrations may be seen.

2. The combination set forth in claim 1, in which said window comprises a hub member having an opening therein positioned over an opening in said tank and of larger diameter than the latter, a lens, a resilient collar encompassing the periphery of said lens and positioned in said hub member, a seal ring having an opening therein positioned over the said lens and aiiixed to the top surface of said hub securely to retain said collar and lens in said opening in said hub.

3. The combination set forth in claim 1, in which the means in said tank to support said rod comprises a substantially U-shaped channel ,member in which said rod is positioned, said channel member extending downwardly into said tank parallel to said rod, and means aixed to the wall of said tank to support said channel member.

4. The combination set forth in claim 1 in which said rod has a collar aixed thereto near the upper end thereof and said stuffing box has a pair of gaskets around said rod and encompassing said collar and means to clamp said gaskets together securely to retain said collar between said gaskets in said stuling box and form a liquid tight seal about said rod.

5. The combination set forth in claim 1 in which said stuffing box comprises a circularhub member having an opening therein positioned over the opening in said tank and of larger diameter than the latter, a pair of gaskets having an opening therein and positioned in the opening of said hub, said gaskets having outstanding rims on the periphery of the faces thereof, said rims abutting to form a cavity, a seal ring having an opening therein and aflixed at its periphery on the upper surface of said hub, said seal ring securely retaining said gaskets in said hub, said rod extending through said openings in said seal ring, said gaskets and said tank and having a collar afixed thereto and positioned in said cavity, said seal ring securely retaining said rod in fixed position.

6. The combination set forth in claim 5 in which a cup shaped cover is provided removably affixed to and encompassing said hub member and the top surface of said cover has an opening therein and a lamp is positioned on said cover over said opening whereby when said opening is positioned over the roughened end of said rod, rays of light from said lamp will be directed thereagainst.

ERVIN C. HAATVEDT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Ruth June 12, 1945 

